Question

Shanice and Jalen are doing an experiment to investigate the law of conservation of mass. They heat a solid in an open container and record the mass of the solid before and after heating. The table shows their observations.

Solid Mass (grams)
before heating 7.5
after heating 5.5

Which best describes the conservation of mass in this experiment?

The law of conservation of mass was broken in this experiment because the mass of the solid decreased.

The law of conservation of mass was not broken because the mass before heating was greater than the mass after heating.

The law of conservation of mass was not broken because the solid was heated in an open container, allowing gases to escape.

The law of conservation of mass was broken in this experiment because the solid was heated in an open container, allowing gases to escape.
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Answer 1

The correct choice is: "The law of conservation of mass was not broken because the solid was heated in an open container, allowing gases to escape."

Explanation: Mass appears to decrease because some material was converted to gas and left the open container. The law applies to a closed system; mass is conserved overall, but it can leave the measured sample if the system is not closed.